Does green tea contain caffeine?
When it first became popular to drink green tea as a health drink, I bought some and tried it out after lunch one day. I never had trouble sleeping, but that night I could not sleep, and tossed and turned until after 4 a.m.
Soon afterwards I checked out the caffeine content and was shocked to discover that green tea often contains more caffeine than black tea. It seems that the younger the leaf, the more caffeine it contains. Young tea leaves can contain up to 5% caffeine, and green tea is frequently made from the youngest leaves.
Green tea is drunk for its flavonoids (known as catechins) and for its stimulating effect on metabolism (which in fact is largely due to the caffeine content). Green tea flavonoids are extremely powerful antioxidants, and this is one case where I think it is worth consuming the caffeine to get the health benefits. If you need to lose some weight, the effect on your metabolism is likely to help (see research), though you should be aware that too much caffeine can over-stimulate your nervous system, causing cause anxiety, a ‘wired’ feeling and insomnia.